Light absorbing barrier for LED fabrication processes

Patent metadata

Field	Value
Publication number	US-11901477-B2
Application number	US-202117350523-A
Country	US
Kind code	B2
Filing date	Jun 17, 2021
Priority date	Jun 17, 2021
Publication date	Feb 13, 2024
Grant date	Feb 13, 2024

Abstract

Exemplary processing methods include forming a group of LED structures on a substrate layer to form a patterned LED substrate. A light absorption barrier may be deposited on the patterned LED substrate. The methods may further include exposing the patterned LED substrate to light. The light may be absorbed by surfaces of the LED structures that are in contact with the substrate layer, and the light absorption barrier. The methods may still further include separating the LED structures for the substrate layer. The bonding between the LED structures and the substrate layer may be weakened by the absorption of the light by the surfaces of the LED structures in contact with the substrate layer.

First claim

The invention claimed is:

1. A semiconductor processing method comprising:
forming a group of LED structures on a substrate layer to form a patterned LED substrate, wherein each LED structure of the group of LED structures includes contact pads;
forming a light absorption barrier on the patterned LED substrate, wherein forming the light absorption barrier leaves exposed at least a portion of the contact pads, and the light absorption barrier is operable to absorb greater than or about 50% of light at wavelengths shorter than or about 300 nm;
forming a reflective layer on the light absorption barrier, wherein the light absorption barrier is between the LED structures and the reflective layer, the reflective layer is operable to reflect light emitted from the LED structures that passes through the light absorption barrier, and forming the reflective layer exposes the at least a portion of the contact pads:
exposing the patterned LED substrate to light, wherein the light is absorbed by surfaces of the LED structures in contact with the substrate layer and the light absorption layer; and
separating the LED structures from the substrate layer, wherein bonding between the LED structures and the substrate layer has been weakened by the absorption of the light by the surfaces of the LED structures in contact with the substrate layer.

2. The semiconductor processing method of claim 1 , wherein the group of LED structures comprises gallium-and-nitrogen-containing material, and wherein the gallium-and-nitrogen-containing material generates nitrogen gas when exposed to the light at the surfaces of the LED structures in contact with the substrate layer.

3. The semiconductor processing method of claim 1 , wherein the substrate layer comprises sapphire.

4. The semiconductor processing method of claim 1 , wherein the light is characterized by a peak intensity wavelength less than or about 300 nm.

5. The semiconductor processing method of claim 1 , wherein the light absorption barrier comprises one or more layers of dielectric material, and wherein the dielectric material is characterized by a room-temperature bandgap of greater than or about 4.3 eV.

6. The semiconductor processing method of claim 1 , wherein the light absorption barrier is operable to transmit greater than or about 50% of light at wavelengths greater than or about 350 nm.

7. The semiconductor processing method of claim 1 , wherein the semiconductor further comprises a backplane substrate bonded to the group of LED structures opposite the substrate layer.

8. The semiconductor processing method of claim 7 , wherein the light absorption barrier prevents the light exposing the patterned LED substrate from reaching the backplane substrate.

9. The semiconductor processing method of claim 1 , wherein forming the group of LED structures on the substrate layer to form the patterned LED substrate comprises:
forming an n-doped layer on the substrate layer, wherein the n-doped layer is a gallium-and-nitrogen-containing material;
forming a multi-quantum-well (MQW) structure layer on the n-doped gallium-and-nitrogen-containing layer;
forming a p-doped layer on the MQW structure layer;
etching the n-doped layer, the MQW structure layer, and the p-doped layer to form an exposed portion of the n-doped layer and an exposed portion of the p-doped layer;
forming an n-pad of the contact pads on the exposed portion of the n-doped layer; and
forming a p-pad of the contact pads on the exposed portion of the p-doped layer.

10. The semiconductor processing method of claim 1 , wherein the light absorption barrier has a thickness of between 25 nm and 400 nm.

11. The semiconductor processing method of claim 1 , wherein the reflective layer has a thickness of between 50 nm and 300 nm.

12. The semiconductor processing method of claim 1 , wherein the light absorption barrier comprises one or more layers of a first dielectric material and one or more layers of a second dielectric material, wherein the first dielectric material and the second dielectric material are different materials, wherein the first dielectric material and the second dielectric material are selected from the group comprising silicon oxide, silicon nitride, titanium oxide, titanium nitride, germanium oxide, tantalum oxide, tantalum nitride, manganese oxide, niobium oxide, antimony oxide, indium-tin-oxide, lanthanum oxide, yttrium oxide, zirconium oxide, aluminum oxide, aluminum nitride, hafnium oxide, and magnesium fluoride.

13. The semiconductor processing method of claim 1 , wherein the reflective layer comprises a metal selected from the group comprising aluminum, silver, and copper.

14. The semiconductor processing method of claim 1 , further comprising forming a light-conversion region in contact with at least one of the LED structures, wherein the light-conversion region is operable to absorb light generated by the LED structures and emit converted light characterized by a longer peak intensity wavelength than light generated by the LED structures.

15. The semiconductor processing method of claim 14 , wherein the light-conversion region is a quantum dot layer operable to convert a shorter wavelength of light generated by the LED structures into one of red, green, or blue light.

16. A semiconductor processing method comprising:
forming an LED structure on a substrate layer, wherein the LED structure includes contact pads;
forming a first portion of a light absorption barrier on the LED structure and the substrate layer, wherein forming the light absorption barrier leaves exposed at least a portion of the contact pads, and the light absorption barrier is operable to absorb greater than or about 50% of light at wavelengths shorter than or about 300 nm;
forming at least one additional portion of the light absorption barrier on the first portion of the light absorption barrier;
forming a reflective layer on the light absorption barrier, wherein the light absorption barrier is between the LED structure and the reflective layer, the reflective layer is operable to reflect light emitted form the LED structure that passes through the light absorption barrier, and forming the reflective layer exposes that at least a portion of the contact pads;
exposing the substrate layer to ultraviolet light, wherein the ultraviolet light is absorbed by exposed portions of the light absorption barrier; and
separating the LED structure from the substrate layer.

17. The semiconductor processing method of claim 16 , wherein the first portion of the light absorption barrier comprises a first dielectric material selected from a group comprising silicon oxide, silicon nitride, titanium oxide, titanium nitride, germanium oxide, tantalum oxide, tantalum nitride, manganese oxide, niobium oxide, antimony oxide, indium-tin-oxide, lanthanum oxide, yttrium oxide, zirconium oxide, aluminum oxide, aluminum nitride, hafnium oxide, and magnesium fluoride.

18. The semiconductor processing method of claim 17 , wherein the at least one additional portion of the light absorption barrier comprises a second portion that includes a second dielectric material that is different than the first dielectric material.

19. The semiconductor processing method of claim 16 , wherein the ultraviolet light is less than or about 300 nm.

20. The semiconductor processing method of claim 16 , wherein a combination of the light absorption barrier and the reflective layer reflect greater than or about 92% of light emitted by the LED structures, wherein light emitted by the LED str

Assignees

• Applied Materials Inc

Inventors

• Pieralisi Fabio
• Zhu Mingwei
• Yang Zihao
• Zhao Liang
• Franklin Jeffrey L
• Ng Hou T
• Patibandla Nag

Classifications

• H10W90/00

  Package configurations · CPC title

• H10H29/8421

  Reflective coatings, e.g. dielectric Bragg reflectors · CPC title

• H10H20/018

  Bonding of wafers · CPC title

• H10H20/841 Primary

  Reflective coatings, e.g. dielectric Bragg reflectors · CPC title

• H10H29/01

  Manufacture or treatment · CPC title